Process for producing mantles for incandescent gas-lighting.



, 'ble of causing them to swell without disso UNTTED STr-iTFJS PATENTUFFTCE.

JOSEPH ARMAND ERNEST HUBERT BOULLIER, OF PARIS, FRANCE.

PROCESS FOR PRODUCING MANTLES FOR INCANDESCENT GAS-LIGHTING.

Specification of Letters Patent.

Patented Feb. 19, 1907.

Application filed March 23, 1303. Serial F0. 149,199.

To all whom, it may concern.-

In order to enable the nature ofthis inven- Be it known that 1', JosnrrrAR -AND EnN- l tion to be clearly understood, the following EsT HUBERTBOULLIER, a citizen of the lie- 1 example is given for the purpose ofshowing public of France, residing at Paris, France, 1 hey it maybecarried out) Nitric acid re seave invented Improvements in the Processfor Producing Mantles for Incandescent Gas- Lighting, of which thefollowing is a specification.

Many attempts have been made to produce incandescent gas1nantles fromartificial silk and the like.

All the processes heretofore proposed have consisted in introducingincandescing comounds into-a viscous solution ofnitrocelluose capable-ofbeing spun into filaments, s inning th e viscous mass into filaments,and then denitrating the same.

Nitrocellulose filaments are not penetrated by water, and they aretherefore not adapted to fix incandcscing compounds; but they ac-(1}?116 this property in a high degree when t ey are treated withliquids which are capa- 'ing them. Certain acidssuch as formic acid,acetic acid, and nitric acid in suitable erty.

The following table discloses the possible and preferred dilutions ofsuch acids for use in my process:

Possible Preferred proportions. proportions.

60 to so. Acptilc acid, (crystallizable,) 75

f 4 z. 40 to 20. Water, H2O to .30. Nitric acid, HNO to 50. atcr, H2O 5Oto 100. Formic acid, CH O 10 to 0. Water, 1110 0 As appears from theabove table, formic acid is used undiluted and at its maximumconcentration. The same result may also be obtained by using alcoholmixed with a-small quantity of commercial ether or with alcoholic ethers(ether salts) or with acetone and generally with any liquids orsubstances which alone or undiluted are capable of dissolvingnitrocellulose. By reason of the presence of a liquid which has nodissolving action on nitrocellulose these mixtures may effect theswelling of the said filaments without dissolving them. The filamentsthus phys icslly modified are still nitrocellulose; but they haveacquired the p .operty of absorbish their absorbent capacity.

lies of iucandescing salts.

leeted as an example, because this acid is the cheapest; but theoperation would be equally successful with concentrated formic acid ofabout ninet -five-per-cent. strength or with crystallizab e acetic acidmixed with a small quantity of water. The degree of dilution of theseacids may vary according to the tempcrature at which the operation iseffected. The other liquids referred to hereinbefore may also beemployed. It is to be understood that all the operations hereinafter described are equally applicable to nitrocellulose ainents as well as toknitted or Woven fabrics made of these filaments.

The process is as follows:

. First. The filaments of nitrocellulose are introduced into the dilutednitric acid of referably 35 01' 36 Ba'um, and they are eft to maceratein the acid until they have swelled up considerably. They have nowbecome transparent or opaline and have a gelatinous appearance. Severalhours are re uired in order to produ e this result at or inaryatmospheric temperature; but the transformation is much more rapid at aterm perature of about 35 Celsius. When the filaments have assumed theappearance above described, they are taken out of the acid, washed, andthen treated in a centrifugal machine, and then they may be dried or notdried, as desired; but for the following operations it is-preferable toemploy the filaments in the moist state, so as not to dimin- Thisoperation not only renders t e filaments ada ted to fix theincandescing' salts, but also e iminates any mineral matters which maybe contained in the nitrocellulose and which would injuriously affectthe illuminating power or the strength of the filament.

Second. The nitrocellulose filaments thus modified are then immersed ina solution of, for instance, one hundred parts of commercialincandcscing nitrates to one hundred parts of water. These proportionswill vary according to the weight of the incandescing compounds which itis desired to fix in the filaments. After several hours of impregnationand even much less, especially if the opof heat, the filaments are takenout of the 1 bath, then treated in a centrifugal machine or squeezed forthe purpose of eliminating therefrom the portion of the solution whichhas not become fixed. Then the filaments are left to dry at a gentletemperature.

Third. These filaments ofnitrocellulose thus-impregnated and dried are'subjected'to a denitrating process, such as the processes ofdenitration employed at present in the manufacture of artificial silk,but, by preference, to treatment with hydrated sulfate of ammonia,because it does not introduce into the filament any foreign substancewhich cannot be removed by washing with water.

The filaments produced by these operatlons are knitted or'woven intomantles, or if the mantle itself has been treated the only remainingoperation is to incinerate the mantle.

By this invention mantles may be'produced lighting from nitrocellulose,said method consisting of first subjecting nitrocellulose filaments to asubstance capable of causing said filaments to swell without dissolutionand after thus causing them to swell, impregnating them withinca'ndescing compounds.

Signed at Paris, France, this 7th day of March, 1903.

JOSEPH ARMANI) ERNEST HUBERT BOULTIIER.

Witnesses:

BENJAMIN BLOCHE, AUGUSTUS E. INGRAM.

